A fuel cell that has a membrane electrode assembly clipping an electrolyte membrane with an anode and a cathode and generates an electric power by an electrochemical reaction of an anode gas supplied to the anode and a cathode gas supplied to the cathode is attracting attention as an energy source. In a fuel cell system with such a fuel cell, it is suggested to circulate an exhaust gas discharged from the anode with a circulation pump and supply it to the anode again, from the viewpoint of improvement of the fuel consumption (see Japanese Laid-Open Patent Publication No. 2012-43677).
When the temperature of the circulation pump circulating the exhaust gas discharged from the anode is low in starting up the fuel cell system and during the driving of the fuel cell system, a condensed water is likely to occur in the circulation pump by a temperature difference between the circulation pump and the exhaust gas. When the circulation pump is driven in a state where the condensed water occurs in the circulation pump, the noise vibration (NV) may get worse.